515851993 has 2 divisors, whose sum is σ = 515851994. Its totient is φ = 515851992.

The previous prime is 515851967. The next prime is 515852009. The reversal of 515851993 is 399158515.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 375855769 + 139996224 = 19387^2 + 11832^2 .

It is a cyclic number.

It is not a de Polignac number, because 515851993 - 2²⁵ = 482297561 is a prime.

It is a super-2 number, since 2×515851993² = 532206557364144098, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (515851933) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 257925996 + 257925997.

It is an arithmetic number, because the mean of its divisors is an integer number (257925997).

Almost surely, 2^515851993 is an apocalyptic number.

It is an amenable number.

515851993 is a deficient number, since it is larger than the sum of its proper divisors (1).

515851993 is an equidigital number, since it uses as much as digits as its factorization.

515851993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 243000, while the sum is 46.

The square root of 515851993 is about 22712.3753271207. The cubic root of 515851993 is about 802.0012359979.

The spelling of 515851993 in words is "five hundred fifteen million, eight hundred fifty-one thousand, nine hundred ninety-three".